[Windows] Begin decoupling text input plugin from the view (#47833)

Currently the text input plugin is strongly tied to a single view. This change makes the text input plugin tied to the engine in preparation for multi-view world.

Part of flutter/flutter#115611

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: loic-sharma

ci/licenses_golden/licenses_flutter

@@ -7166,7 +7166,6 @@ ORIGIN: ../../../flutter/shell/platform/windows/text_input_manager.cc + ../../..
 ORIGIN: ../../../flutter/shell/platform/windows/text_input_manager.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/windows/text_input_plugin.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/windows/text_input_plugin.h + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/shell/platform/windows/text_input_plugin_delegate.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/windows/window_binding_handler.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/windows/window_binding_handler_delegate.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/shell/platform/windows/window_proc_delegate_manager.cc + ../../../flutter/LICENSE
@@ -9990,7 +9989,6 @@ FILE: ../../../flutter/shell/platform/windows/text_input_manager.cc
 FILE: ../../../flutter/shell/platform/windows/text_input_manager.h
 FILE: ../../../flutter/shell/platform/windows/text_input_plugin.cc
 FILE: ../../../flutter/shell/platform/windows/text_input_plugin.h
-FILE: ../../../flutter/shell/platform/windows/text_input_plugin_delegate.h
 FILE: ../../../flutter/shell/platform/windows/window_binding_handler.h
 FILE: ../../../flutter/shell/platform/windows/window_binding_handler_delegate.h
 FILE: ../../../flutter/shell/platform/windows/window_proc_delegate_manager.cc

shell/platform/windows/cursor_handler_unittests.cc

@@ -63,13 +63,13 @@ class CursorHandlerTest : public WindowsTest {
   FlutterWindowsView* view() { return view_.get(); }
   MockWindowBindingHandler* window() { return window_; }
 
-  void use_headless_engine() {
+  void UseHeadlessEngine() {
     FlutterWindowsEngineBuilder builder{GetContext()};
 
     engine_ = builder.Build();
   }
 
-  void use_engine_with_view() {
+  void UseEngineWithView() {
     FlutterWindowsEngineBuilder builder{GetContext()};
 
     auto window = std::make_unique<MockWindowBindingHandler>();
@@ -93,7 +93,7 @@ class CursorHandlerTest : public WindowsTest {
 };
 
 TEST_F(CursorHandlerTest, ActivateSystemCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -119,7 +119,7 @@ TEST_F(CursorHandlerTest, ActivateSystemCursor) {
 }
 
 TEST_F(CursorHandlerTest, ActivateSystemCursorRequiresView) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -146,7 +146,7 @@ TEST_F(CursorHandlerTest, ActivateSystemCursorRequiresView) {
 }
 
 TEST_F(CursorHandlerTest, CreateCustomCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -177,7 +177,7 @@ TEST_F(CursorHandlerTest, CreateCustomCursor) {
 }
 
 TEST_F(CursorHandlerTest, SetCustomCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -217,7 +217,7 @@ TEST_F(CursorHandlerTest, SetCustomCursor) {
 }
 
 TEST_F(CursorHandlerTest, SetCustomCursorRequiresView) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -258,7 +258,7 @@ TEST_F(CursorHandlerTest, SetCustomCursorRequiresView) {
 }
 
 TEST_F(CursorHandlerTest, SetNonexistentCustomCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -287,7 +287,7 @@ TEST_F(CursorHandlerTest, SetNonexistentCustomCursor) {
 }
 
 TEST_F(CursorHandlerTest, DeleteCustomCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());
@@ -325,7 +325,7 @@ TEST_F(CursorHandlerTest, DeleteCustomCursor) {
 }
 
 TEST_F(CursorHandlerTest, DeleteNonexistentCustomCursor) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   CursorHandler cursor_handler(&messenger, engine());

shell/platform/windows/flutter_windows_engine.cc

@@ -666,7 +666,7 @@ FlutterWindowsEngine::CreateKeyboardKeyHandler(
 
 std::unique_ptr<TextInputPlugin> FlutterWindowsEngine::CreateTextInputPlugin(
     BinaryMessenger* messenger) {
-  return std::make_unique<TextInputPlugin>(messenger, view_);
+  return std::make_unique<TextInputPlugin>(messenger, this);
 }
 
 bool FlutterWindowsEngine::RegisterExternalTexture(int64_t texture_id) {

shell/platform/windows/flutter_windows_view.h

@@ -20,7 +20,6 @@
 #include "flutter/shell/platform/windows/angle_surface_manager.h"
 #include "flutter/shell/platform/windows/flutter_windows_engine.h"
 #include "flutter/shell/platform/windows/public/flutter_windows.h"
-#include "flutter/shell/platform/windows/text_input_plugin_delegate.h"
 #include "flutter/shell/platform/windows/window_binding_handler.h"
 #include "flutter/shell/platform/windows/window_binding_handler_delegate.h"
 #include "flutter/shell/platform/windows/window_state.h"
@@ -30,10 +29,9 @@ namespace flutter {
 // ID for the window frame buffer.
 inline constexpr uint32_t kWindowFrameBufferID = 0;
 
-// An OS-windowing neutral abstration for flutter
-// view that works with win32 hwnds and Windows::UI::Composition visuals.
-class FlutterWindowsView : public WindowBindingHandlerDelegate,
-                           public TextInputPluginDelegate {
+// An OS-windowing neutral abstration for a Flutter view that works
+// with win32 HWNDs.
+class FlutterWindowsView : public WindowBindingHandlerDelegate {
  public:
   // Creates a FlutterWindowsView with the given implementor of
   // WindowBindingHandler.
@@ -186,11 +184,12 @@ class FlutterWindowsView : public WindowBindingHandlerDelegate,
   // |WindowBindingHandlerDelegate|
   virtual gfx::NativeViewAccessible GetNativeViewAccessible() override;
 
-  // |TextInputPluginDelegate|
-  void OnCursorRectUpdated(const Rect& rect) override;
+  // Notifies the delegate of the updated the cursor rect in Flutter root view
+  // coordinates.
+  virtual void OnCursorRectUpdated(const Rect& rect);
 
-  // |TextInputPluginDelegate|
-  void OnResetImeComposing() override;
+  // Notifies the delegate that the system IME composing state should be reset.
+  virtual void OnResetImeComposing();
 
   // Called when a WM_ONCOMPOSITIONCHANGED message is received.
   void OnDwmCompositionChanged();

shell/platform/windows/platform_handler_unittests.cc

@@ -142,13 +142,13 @@ class PlatformHandlerTest : public WindowsTest {
  protected:
   FlutterWindowsEngine* engine() { return engine_.get(); }
 
-  void use_headless_engine() {
+  void UseHeadlessEngine() {
     FlutterWindowsEngineBuilder builder{GetContext()};
 
     engine_ = builder.Build();
   }
 
-  void use_engine_with_view() {
+  void UseEngineWithView() {
     FlutterWindowsEngineBuilder builder{GetContext()};
 
     auto window = std::make_unique<NiceMock<MockWindowBindingHandler>>();
@@ -166,7 +166,7 @@ class PlatformHandlerTest : public WindowsTest {
 };
 
 TEST_F(PlatformHandlerTest, GetClipboardData) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -190,7 +190,7 @@ TEST_F(PlatformHandlerTest, GetClipboardData) {
 }
 
 TEST_F(PlatformHandlerTest, GetClipboardDataRejectsUnknownContentType) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -203,7 +203,7 @@ TEST_F(PlatformHandlerTest, GetClipboardDataRejectsUnknownContentType) {
 }
 
 TEST_F(PlatformHandlerTest, GetClipboardDataRequiresView) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -217,7 +217,7 @@ TEST_F(PlatformHandlerTest, GetClipboardDataRequiresView) {
 }
 
 TEST_F(PlatformHandlerTest, GetClipboardDataReportsOpenFailure) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -237,7 +237,7 @@ TEST_F(PlatformHandlerTest, GetClipboardDataReportsOpenFailure) {
 }
 
 TEST_F(PlatformHandlerTest, GetClipboardDataReportsGetDataFailure) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -261,7 +261,7 @@ TEST_F(PlatformHandlerTest, GetClipboardDataReportsGetDataFailure) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardHasStrings) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -282,7 +282,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStrings) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardHasStringsReturnsFalse) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -303,7 +303,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStringsReturnsFalse) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardHasStringsRejectsUnknownContentType) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -315,7 +315,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStringsRejectsUnknownContentType) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardHasStringsRequiresView) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -330,7 +330,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStringsRequiresView) {
 
 // Regression test for https://github.com/flutter/flutter/issues/95817.
 TEST_F(PlatformHandlerTest, ClipboardHasStringsIgnoresPermissionErrors) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -350,7 +350,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStringsIgnoresPermissionErrors) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardHasStringsReportsErrors) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -370,7 +370,7 @@ TEST_F(PlatformHandlerTest, ClipboardHasStringsReportsErrors) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardSetData) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -397,7 +397,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetData) {
 
 // Regression test for: https://github.com/flutter/flutter/issues/121976
 TEST_F(PlatformHandlerTest, ClipboardSetDataTextMustBeString) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -409,7 +409,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetDataTextMustBeString) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardSetDataUnknownType) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -421,7 +421,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetDataUnknownType) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardSetDataRequiresView) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine());
@@ -435,7 +435,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetDataRequiresView) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardSetDataReportsOpenFailure) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -455,7 +455,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetDataReportsOpenFailure) {
 }
 
 TEST_F(PlatformHandlerTest, ClipboardSetDataReportsSetDataFailure) {
-  use_engine_with_view();
+  UseEngineWithView();
 
   TestBinaryMessenger messenger;
   PlatformHandler platform_handler(&messenger, engine(), []() {
@@ -478,7 +478,7 @@ TEST_F(PlatformHandlerTest, ClipboardSetDataReportsSetDataFailure) {
 }
 
 TEST_F(PlatformHandlerTest, PlaySystemSound) {
-  use_headless_engine();
+  UseHeadlessEngine();
 
   TestBinaryMessenger messenger;
   MockPlatformHandler platform_handler(&messenger, engine());
@@ -496,7 +496,7 @@ TEST_F(PlatformHandlerTest, PlaySystemSound) {
 }
 
 TEST_F(PlatformHandlerTest, SystemExitApplicationRequired) {
-  use_headless_engine();
+  UseHeadlessEngine();
   UINT exit_code = 0;
 
   TestBinaryMessenger messenger([](const std::string& channel,
@@ -518,7 +518,7 @@ TEST_F(PlatformHandlerTest, SystemExitApplicationRequired) {
 }
 
 TEST_F(PlatformHandlerTest, SystemExitApplicationCancelableCancel) {
-  use_headless_engine();
+  UseHeadlessEngine();
   bool called_cancel = false;
 
   TestBinaryMessenger messenger(
@@ -539,7 +539,7 @@ TEST_F(PlatformHandlerTest, SystemExitApplicationCancelableCancel) {
 }
 
 TEST_F(PlatformHandlerTest, SystemExitApplicationCancelableExit) {
-  use_headless_engine();
+  UseHeadlessEngine();
   bool called_cancel = false;
   UINT exit_code = 0;